maltby



(No Model.) 2 Sheets-Sheet 1 S. MALTBY.

PISTON.

No.- 277,305. Patented May 8,1883.

77137295866; I j i r ug 7 yr" b Szdne y Jliali yj; 5 6 g/QM W u PETERS.PholvLilhognph-r. Washington, a. c.

2 Sheets-Sheet; 2.

(No Model.)

S. MALTBY.

PISTON.

Patented May 8,1883.

Inuen Z07 Nil/teases Sidney Malay N, PETERS Phmo-Lhhn m bcr, Washinginn.0.6.

ATENT FFICEe- SIDNEY MALTBY, OF WASHINGTON, DISTRICT OF COLUMBIA,ASSIGNOR OF ONE-HALF TO EDWARD L. LAMBIE, OF SAME PLACE.

PISTON.

SPECIFICATION forming part of Letters Patent No. 277,305, dated May 8,1883.

Application filed March 10, 1883. (No model.)

To all whom it may concern Be it known that I, SIDNEY MALTBY,.a citizenof the United States, residing at \Vashington, in the District ofColumbia, have invented certain new and useful Improvements in Pistons,of which the following is a specification, reference being had thereinto the accompanying drawings.

This inven tion relates, generally, to that class of pistons in whichthe packing is set out by pressure of steam, air, gas, or othersimilarlyacting agent; and it has especial reference to means torregulating and controlling the pressure exerted in setting out thepacking, so that the latter will be prevented from excessively andunevenly wearing the inner surface of the cylinder or barrel in whichthe piston plays.

The object of the invention is to provide means whereby the pressurewhich sets out the packing will be applied independently of the pressurewhich drives the piston.

It has the further object to provide means whereby the setting-outpressure of the packing may be regulated while the engine of which thepiston forms a part is in motion, and also to enable thesupplying oflubrication to the interior of the cylinder, while the engine is in.motion, through the devices used for applying the setting-out pressureof the pack- 0 ing.

My improvement consists in certain novel constructions and combinationsof devices, whichwill be clearly understood by reference to theaccompanying drawings and the following specification, and which will bedefinitely pointed out in the appended claims.

In the drawings, Figure 1 is a longitudinal vertical section of asteam-engine cylinder and piston having my improvement applied there- 0to. Fig. 2 is a similar section illustrating a modification ofmyinvention. Fig. 3 is asimilar section illustrating a modification ofthe invention adapted to applying air-pressure for setting out thepacking. Fig. 4 is a similar 4 5 section illustrating anothermodification of devices for applying air-pressure for setting out thepacking. Fig. 5 is a side view of a preferred form of expansiblepacking-ring, and Fig. 6 is a section of the same on the line 00 a:

of Fig. 5.

Referring to Fig. 1, the letter A indicates the steam-cylinder, and Bits piston, to which is connected a hollow piston-rod, (J, which playsthrough a stuffing-box in the head of the cylinder in the usual manner..The piston B is composed in the present instance of two heads, I) b,separated by hub 11, through which and both of the heads I) b the rod (3passes and is secured by nuts e. -The bore or central passage of the rod0 has a lateral open ing between the heads of the piston, and thisopening connects with a passage,.cl, to the interior chamber of thepiston through the hub d.

In the opposite heads of the piston are 6 formed openings or ports f,which are closed on the inside by spring-pressed valves g,-whioh slideupon a rod, [1-, which is screwed through one of the heads of the pistonand enters a socket in the other. The valves 9 are simply disks orcollars perforated centrally to receive the rod, and against which bearthe opposite ends of a light spring, i, which has a sufficient tensionto keep both valves normally closed, but will permit either to readilyopen in response to pressure on its outer face. It will be observed thatwhen one of the valves opens the tendency of the spring 6 will be topress the other valve to its seat with increased pressare.

Near its outer end the hollow piston-rod has its bore intersected by ashort vertical tube, K, the top of which is provided with a hollow cap,k.

In the upper end of tube K is fitted a valve, 1, upon which bears oneend of a spring, in, the upper end of which bears against a plate, m,upon which impinges the tip of a hand-screw, n, which passes through thehead of the cap k.

To the pipe K is connected, in a well-known manner, the pressure-gage O,of any ordinary construction, adapted to indicate steam or other fluidpressure. With the cap is is connected, above the valve 1, a smallprojecting pipe, 12, open at its outer end.

The letter Q indicates an expansible packing-ring, which is locatedbetween the heads of the piston, and may be ofany suitable knownconstruction, but preferably that which will be hereinafter described. Asingle packing-ring may be used, or two or more, side by side.

The operation of the invention as now the icribed is as follows Whensteam is admitted the cylinder on one side of the piston and lrives thesame the valve 9 on the side to vhich steam is admitted will be forcedopen, ind steam will enter the interior of the piston Llld. set out thepacking-rings, and will at the ,ame time flow through the passage (1 andthe )ore of the piston-rod to the tube K, where it :Xerts a pressureupon the valve 1 and the )ressure-gage. It will now be observed that )yproperly regulating the degree of force vith which the spring at pressesthe valve lto ts seat said valve may be caused to open and 'elieve thepressure within the piston and igainst the packing-rings whenever thatpressire exceeds apredetermined point. Thepressire within the piston,its hollow rod, and tube K will obviously be the same, and this pressirewill be indicated by the gage 0, so that ;he amount of force with whichthe packing- ."ings are pressed against the inner face of the :ylindercan be readily ascertained by observation of said gage. For example, itit is known that a pressure of fifteen pounds will set out thepacking-rings properly the tension if the spring in will be regulated bymeans of the hand-screw n so that the pressure-gage will indicate apressure of fifteen pounds without the valve i being opened;butimrnediately that pressure is exceeded said valve will open and allowthe excess to escape into the cap it and through the vent-tube 1). Itwill now be seen that however great may be the pressure with which thepiston is driven the pressure which sets out the packing-rings can neverexceed the point at which the valve l has been regulated to open, andthis setting-out pressure will be maintained uniformly throughout thestroke of the piston in both directions. It will also be observed thatat whatever point the engine may be stopped both valves 9 y will beautomatically closed by the pressure of the spring between them and thesteam within the piston and the steam-pressure in said piston will beretained and keep the packing rings well set out, so that the engine maybe again promptly started, as no leakage past the piston will occur whensteam is again admitted to the cylinder.

The letter R indicates an oil-cup attached to the piston-rod andconnected with its bore, so that lubrication may be at any time appliedthrough said piston-rod and find its way to the interior of the piston,whence it will be forced outward through thejoints of the-packing ringor rings. Thus it will be seen that the setting-out pressure of thepacking may be regulated or lubrication applied at any time withoutstopping the engine for such purposes.

In the modification shown in Fig.2 the piston is constructed the same asshown in Fig. 1; but instead of making the piston-rod hollow I lead aseparate hollow rod, S, from the interior of the piston, and this rodpasses through a boss, S, which is screwed into the cylindenhead andprojects outwardly, said,

boss being provided at its outer end with a suitable stuffing-box forthe passage of said hollow rod. To the outer end of the boss S issecured a sleeve, S which projects outwardly, is closed at its outerend, and surrounds the hollow rod S. Into the boss S is screwed the tubeK, which is identical with the tube K in Fig. 1, and is provided with asafety-valve and pressure-gage in the same manner. From the tube K apassage, S leads through the boss S to the interior of the sleeve S.From the cap 70, above the safety-valve, a pipe, t, leads to thewaste-pipe t, which is connected with pet; cook it, so that the escapeof steam from the safety-valves will be carried oft and not observedwithin the vicinity of the engine. In

the sleeve S.

The operation of the modification now described will be readilyunderstood. The steam which finds its way to the interior of the pistonthrough either of the valves 9 flows through the hollow rod S, throughthe sleeve S", andthence through the passage S and tube K to thesafety-valve land pressure-gage 0, so that whenever the pressure withinthe piston and against the packing-rings exceeds the force under whichthe valve Z is regulated to open said valve will automatically relievethe pressure, and a uniform pressure will thus be maintained behind thepacking-rings.

In the modification of my invention illustrated in Fig. 3 the devicesare adapted for applying air-pressure for setting out the packing-ringsof the piston of a steam -engine, though they may be similarly appliedto an engine driven by any other motive agent. In this modification thepiston-heads have no valves for admitting steam to the interior, and thehollow rod S, which leads from the interior of the piston, acts as theplunger of an air-pump, which consists of a barrel or sleeve, "S", whichis inserted within the sleeve S and surrounds the hollow rod, its innerend be- :ing supported by being inserted in an an- .nular groove orrecess in the outer end of the boss S, and its outer end supported bybeing passed through and screwed into an opening formed to receive it inthe head of the sleeve S The hollow rod S is provided with apiston-head, s, which plays air-tight in the inner sleeve or barrel, Sand in the outer end of said hollow rod is arranged a valve, a, whichopens inwardly with respect to the rod. In the outer end or head of thesleeve S is formed an opening or port, a, which is guarded by a valve,which opens inwardly. Behind its piston-head an opening, 8, is formed inone sideof the rod S and an opening, 8 is formed in the sleeve S nearits inner end. The arrangement of the tube K and its connections on theboss S is the same as shown in Fig. 2, except that the ventpipe if neednot lead to the waste-pipe. The operation of this modification is asfollows: When the engine is at rest the sleeves become filled with air,as

this instance an cheap, It, is connected with the valves of the rod Sand sleeve S are not IIO normally pressed to their seats with sufficientforce to prevent access of air to the interior of said sleeves. Now,supposing the engine to be started on its outstroke, the hollow rod 8and its head will move inwardly, and the air which is behind it will becompressed and driven partly through the opening s and the bore of therod to the interior of the piston,and partly through the opening 8 tothe space between the two sleeves, and through the passage S and tube Kto the safety-valve and pressuregage. The portion which enters. thepistonchamber acts by its pressure to set out the packing-rings; and asthere is free comm unication between the interior chamber of the pistonand the tube K it is obvious that the compressed air will exert an equalpressure upon the packing-rings and the safety-valve, and this valvebeing regulated, as heretofore described, to open under a given amountof pressure, it is obvious that this predetermined amount of pressurecan never be exceeded onsaid packing-rings. As the rod and its head moveinwardly air is drawn into the barrel or or sleeve Si, past the valve aand when the piston is on itsinstroke the valve it opens, and this airis forced partly in through the hollow rod to the interior of thepiston, and partly through the opening 8, sleeve S and opening 8 to thesleeve S and thence through the passage S to the safety-valve andpressuregage, its pressure upon the packing-rings being controlled inthe same manner as when the piston was on its outstroke.

In the modification illustrated in Fig. 4, the letter (3 representsahollow piston-rod, the end of which projects out through a stuflingboxin the cylinder-head B. This is the opposite end of the rod from thecross-head. D is a piston-head made in two parts bolted together, andhaving between them an annular chamber, in which a packing-ring, Q, isplaced in the usual manner. This chamber communicates by passages 6 withthe hollow piston-rod .0. To the end of the said rod is attached thereceiver F of an air-pump, G. This pump and receiver are carried backand forth with the rod and the pump is so arranged as to be operated bythis movement, its piston-rod H passing through a projection, 1 on thecylinder-head, and having an adjustable stop, J, by means of which itsstrokes may be regu-' lated. In the top of the receiver is arranged thesafety-valve l for regulating the air-pressure, and to the side of thereceiver is attached the gage O for indicating the pressure within. Theoperation of this modification is as follows: When the piston is workingthe airpump supplies the receiver with air, and there being a directcommunication between the said receiver and the chamber of the pistonthrough the hollow piston-rod, the packingring Q is forced outwardagainst the inner S1111. face of the cylinder in accordance with thedegree of pressure in said receiver, thus independently employing anunvarying force for setting out the packing-rings independently to arodprojecting through the rear head of the cylinder, they may be carriedby the crosshead of the piston-rod, which maybe bored to communicatewith the chamber of the piston.

The form of packing-ring which I prefer to use, and which is illustratedin Figs. 5 and 6, is formed of segments 10, which are placed end to endto for'm a complete packing-ring, W. These segments are connectedtogether by metallic spring-plates 10, attached to their innersurfaces,one end of one of these plates being attached firmly to one segment andloosely to the adjacent segmentby means of a pin, 20 which projects fromthe segment through a small longitudinal slot, 10 in the end of theplate. The segments are thus well connected together to form a ring, butmay separate sufficiently at their ends to allow the ring to expandproperly. In using two or more of these rings, I prefer to arrange themso that the segments will break joints--that is, the joint between anytwo segments of a ring will stand opposite a solid portion of a segmentof an adjacent ring.

Having now fully described my invention and explained the operationthereof, I wish it tobe understood that I do not confine myself to theprecise construction and arrangement of parts as illustrated in mydrawings, but may vary the same by the substitution of equiyalents forany of said parts, and may rearrange and modify the general constructionof the apparatus in any manner for the better carrying out of myinvention without departing from the essential principle thereof.

That I claim is 1. Thecombination, with a chambered piston andexpansible packing, of devices for applying to the packing a setting-outpressure different from the pressure used to drive the piston,-and meansfor automatically regulat-- ing said setting-out pressure, substantiallyas described.

'2. The combination, with a chambered piston and an expansible packingring or rings arranged to close the outer opening of said chamber, of ahollow rod leading out from the interior of the piston, and automaticmeans for controlling pressure in the interior of the piston throughsaid hollow rod, substantially as described.

3. The combination, with a chambered piston and an expansible packingring or rings arranged at the outer opening of the pistonchamber, andmeans for supplying pressure within said piston-chamber, of a hollow rodleading from the interior of said piston, and anautomatic'regulatin'g-va-lve connected either directly or intermediatelywith said hollow rod, substantially as described.

4. The combination, with a chambered piston adapted to receive anexpansible packing ring or rings in the outer opening of its chamher, ofports and valves for admitting the'piston-driving agent to the interiorof the piston at each side alternately, a hollow rod leading out fromthe interior of the piston, and a safety-valve arranged to control thepressure in the piston through said hollow rod, substantially asdescribed.

5. The combination, with a chambered pis ton adapted to receive anexpansible packing and having ports in the opposite walls of itschamber, of valves arranged to close sa-id ports simultaneously, as aresult of pressure Within said piston, a hollow rod leading from thepiston-chamber and adapted to play through an opening in thecylinder-head, and automatic 1 means for regulating pressure in thepiston through said hollow rod, substantially as described.

6. A packing-ring composed of segments joined end to end by springplateshaving 20 slip-joint connection with said segments, substantially asdescribed.

In testimony whereof I affix my signature in presence of two witnesses.

SIDNEY MALTBY.

YVitnesses:

W. B. HALE, E. L. LAMBIE.

